Fight-fans may feel a pang of nostalgia when they walk past the Department for Education these days. There was, after all, a time when that building hosted some of the fiercest heavyweight scraps in all Westminster: Gove versus Laws, Cummings versus Everyone, etc. But now those old fights belong, like the ones between Jack Dempsey and Gene Tunney, to the sepia fog of time. The modern, Morgan era is much less contentious. The ringside seating has been pulled down.

But rejoice, ye disappointed, for the Coalition has established not one but two new boxing rings – and you won’t have to go far for either. One is that squat and glassy building on Marsham Street. The other is the concrete clunker on Petty France. You’ll know them as the Home Office and the Ministry of Justice.

I thought something might be afoot when Norman Baker resigned from his ministerial role at the Home Office, earlier this month. Now that I’ve read the speech delivered on Tuesday night by Simon Hughes, I’m sure of it. This speech attacked the Conservatives on numerous fronts – including the vexatious and not-entirely-unambiguous issue of books for prisoners – but two stood out: prisons reform and drugs reform. Or, as Hughes put it, ‘the Tory pre-election flirtation with a more enlightened approach to short-sentences and drugs policy have come to nothing.’

As it happens, I think there’s something in what Hughes said (see here and here). But what matters more is how and why he’s saying it. The simple truth is that the Home and Justice departments are probably the Lib Dems’ best remaining battlegrounds, at least in a physical sense. What else is there? The environment: they do try to differentiate themselves on this, but they are in charge of one of the departments responsible, so they can’t go all-out attack. Europe: again, they try, but there’s no one specific department. Universities: ha!

Which leaves their traditional emphasis on civil and social liberties, which are mostly to do with the Home Office and the Ministry of Justice. These are the departments from which they can try to convince their old supporters that they’ve still got it; particularly as this isn’t comfortable territory for Labour. And they’re also departments that accommodate some of their most prominent and proactive MPs, such as Hughes and Lynne Featherstone, as ministers. No doubt they’ll characterise it as taking on the system from the inside.

Actually, now I come to think of it, there is one other department where the Lib Dems have become noticeably more aggressive – and that is the Treasury. One of the refrains of their party conference was that the Tory leadership, with their tax cuts upon tax cuts, are neglecting the task of deficit reduction. Danny Alexander returned to this on Tuesday.

And so we see both halves of what, I imagine, will be the Lib Dems’ two-part election-time message. We’re still the Lib Dems, fighting for your right to smoke weed! But we’ve also been in Government, and are serious about the deficit and stuff! The question is: who will be left bloodied on the canvas at the end of it?